Yes, they do sell wine in grocery stores here in Tampa. But, I'm not sure about you finding a grocery store en route. You are going through downtown areas, mostly industrial. There must be one somewhere, but it won't be easy to find and you could run up a higher cab bill. Look for alternatives, such as convenience stores, liquor stores, etc. Also, make sure Carnival will let you take all of that on board.
Cheers!
Marty